Circular blade sharpening device

Abstract

A sharpening device for a circular-shaped blade of the type used on a rotary meat trimming knife. The blade is rotatably mounted on a power driven blade holder which is movable horizontally along a base. A grinder which includes a motor and a power driven grinding wheel also is movable horizontally along the base whereby the paths of movement of the blade holder and grinder intersect with the grinding wheel engaging the cutting and edge of the blade at a predetermined angle. A sharpening control mechanism has a course advancement consisting of a threaded shaft which is slidably rotatably mounted in the base and is connected to the blade holder by a follower pin whereby rotation or linear movement of the shaft will move the blade holder linearly along the base and bring the blade into contact with the grinding wheel. A vernier control lever is engaged with the threaded shaft and is manually moved by an operator to forwardly advance the blade holder and blade a predetermined linear fine adjustment distance as the grinding wheel is reciprocated along its direction of travel causing momentary linear crossing contact between the grinding wheel and blade cutting edge to remove a predetermined amount of material from the blade cutting edge without generating excess heat in the blade or grinding wheel.

What is claimed is: 
     
       1. A sharpening device for the cutting edge of a circular-shaped knife blade of a meat trimming knife after removal of the blade from the knife, said device including: (a) a base;   (b) a power driven blade holder movably mounted on the base for movement in a predetermined horizontal linear path on said base, said blade holder having an electric drive motor and check means for rigidly mounting the blade for rotation by said motor for preventing relative movement between the blade and the chuck means during sharpening   (c) a grinder having a power driven rotating grinding wheel movably mounted on the base for movement in a horizontal linear path which insects the horizontal linear path of the blade holder whereby the grinding wheel engages and passes beyond the cutting edge of a knife blade mounted on the blade holder at a predetermined angle for sharpening said cutting edge; and   (d) manually actuated sharpening control means for individually reciprocally moving the grinding wheel and blade holder along their respective horizontal paths to bring the wheel into initial contact with the cutting edge of the blade, with said control means further including vernier means for effecting a subsequent predetermined limited horizontal movement along the horizontal linear path of one of the blade holder and grinder to sharpen the blade cutting edge by grinding a predetermined amount of material from the blade by said limited horizontal movement as the other of said blade holder and grinder is reciprocated along its horizontal linear path causing momentary linear crossing contact between the grinding wheel and the blade cutting edge.   
     
     
       2. The sharpening device defined in claim 1 in which the sharpening control means includes a helically threaded shaft slidably rotatably mounted on the base and follower pin means operatively connecting the threaded shaft with one of the blade holder and grinding wheel for moving said one of the blade holder and grinding wheel linearly along the base upon manual rotation of the threaded shaft. 
     
     
       3. The sharpening device defined in claim 2 in which the threaded shaft is spring biased in an outward direction by a coil spring engaged with an inner end of said shaft. 
     
     
       4. The sharpening device defined in claim 3 in which the threaded shaft has a reduced diameter outer end which extends outwardly of the base through a threaded hole formed in the base; in which the vernier means includes a lever having an externally threaded hollow hub threadably mounted in the threaded hole of the base; in which the outer end of the shaft extends through the hollow hub bore; and in which the lever hub abuts against the shaft and upon rotational movement of the hub through a predetermined arcuate distance overcomes the bias of the spring moving said shaft and connected one of the blade holder and grinding wheel a predetermined linear distance to grind a predetermined amount of material from the blade. 
     
     
       5. The sharpening device defined in claim 4 in which a handwheel is mounted on the extended end of the threaded shaft for manually rotating the shaft for linearly moving the connected one of the blade holder and grinding wheel along the base through the connection with the follower pin means. 
     
     
       6. The sharpening device defined in claim 4 in which the predetermined limited linear movement between the blade and grinding wheel affected by the vernier means is approximately 0.01 inches. 
     
     
       7. The sharpening device defined in claim 4 in which the vernier means lever is pivoted through an arc of approximately 55° for obtaining the limited blade sharpening movement. 
     
     
       8. The sharpening device defined in claim 7 in which a stop pin is mounted on the lever and engages the base to regulate the limited pivotal movement of said lever. 
     
     
       9. The sharpening device defined in claim 3 in which a ball is mounted between the inner end of the shaft and the spring. 
     
     
       10. The sharpening device defined in claim 4 in which the base includes a horizontal top surface; and in which guide rails are mounted on the top surface for movably supporting the blade holder and grinding wheel for horizontal movement along said top surface. 
     
     
       11. The sharpening device defined in claim 10 in which the base is formed with horizontally extending cylindrical-shaped opening means for slidably rotatably mounting the threaded shaft therein. 
     
     
       12. The sharpening device defined in claim 2 in which the follower pin means includes a follower pin and a block formed with a horizontal hole through which the threaded shaft extends; in which the said one of the blade holder and grinding wheel is attached to said block; and in which the follower pin is mounted on the block and projects into the horizontal block hole and engages threads formed on the threaded shaft. 
     
     
       13. The sharpening device defined in claim 1 in which the blade holder includes a housing containing the electric motor; in which the means for rigidly rotatably mounting the blade is a collet mounted on the housing; and in which the blade holder is movably mounted on the base on a pair of slide rails. 
     
     
       14. The sharpening device defined in claim 13 in which the sharpening control means is operatively engaged with the blade holder for moving said holder and mounted blade with respect to the grinding wheel. 
     
     
       15. The sharpening device defined in claim 1 in which the grinder includes an electric motor for rotating the grinding wheel; and in which the motor and grinding wheel are movably mounted on a pair of slide rails mounted on the base. 
     
     
       16. The sharpening device defined in claim 15 in which the sharpening control means is operatively cngaged with the grinder for moving the motor and grinding wheel with respect to the blade holder. 
     
     
       17. The sharpening device defined in claim 1 in which the paths of movement of the blade holder and grinder intersect and form an included angle of approximately 65° to provide a 25° angle on the cutting edge of the knife blade. 
     
     
       18. The sharpening device defined in claim 13 in which the blade holder housing is pivotally mounted on a platform; and in which the platform is mounted on the slide rails to provide movement of the blade holder along its horizontal linear path. 
     
     
       19. The sharpening device defined in claim 18 in which the platform is formed with an arcuate-shaped groove; in which locking means is located within the platform groove and is engageable with the blade holder housing for maintaining the housing in a predetermined adjusted position on said platform to effect a predetermined crossing contact angle between the grinding wheel and blade cutting edge. 
     
     
       20. The sharpening device defined in claim 19 in which the locking means includes a rod having a head complementary to the arcuate-shaped platform groove and is slidably moveable in said groove; in which a clamping nut is mounted on the locking means rod and engages the blade holder housing for clamping the housing against the platform to secure said housing in an adjusted position. 
     
     
       21. The sharpening device defined in claim 19 in which stop means is mounted on the platform for limiting the pivotal movement of the blade holder housing thereon. 
     
     
       22. The sharpening device defined in claim 21 in which the stop means includes a pair of set screws which extend into the arcuate-shaped groove and engage the locking means upon the blade holder housing being pivotally moved to a predetermined adjusted position. 
     
     
       23. The sharpening device defined in claim 18 in which the blade holder housing is pivotally moveable through an angle of approximately 65°. 
     
     
       24. The sharpening device defined in claim 15 in which a gear rack is mounted on the grinder motor; and in which a gear is rotatably mounted on a shaft of a handwheel and engages the gear rack for moving the grinding wheel along its linear horizontal path. 
     
     
       25. The sharpening device defined in claim 1 in which the power driven blade holder electric drive motor is reversible. in which the grinder includes an electric drive motor for rotating the grinding wheel; and in which switch means are engageable with the blade holder and grinder for electrically controlling said drive motors. 
     
     
       26. The sharpening device defined in claim 25 in which the switch means include a pair of limit switches having spring biased plungers which are actuated upon a predetermined movement of the grinder motor and blade holder motor. 
     
     
       27. A sharpening device for the cutting edge of a cirular-shaped knife blade for a meat trimming knife after removal of the blade from the knife, said device including: (a) a base;   (b) a power driven blade holder movably mounted on the base for rotatably mounting a knife blade, said blade holder having a housing and a collet for rigidly rotatably mounting the blade for preventing relative movement between the blade and the collet during sharpening, and an electric motor located within the housing for rotating said collet and blade, said blade holder being movable in a predetermined horizontal linear path on said base;   (c) a grinder having a power driven rotating grinding wheel movably mounted on the base for movement in a horizontal linear path which intersects the horizontal linear path of the blade holder whereby the grinding wheel engages and passes beyond the cutting edge of a knife blade mounted on the collet of the blade holder at a predetermined angle for sharpening said cutting edge; and   (d) manually actuated sharpening control means for individually reciprocally moving the grinding wheel and blade holder along their respective horizontal paths to bring the wheel into initial contact with the cutting edge of the blade, with said control means further including vernier means for effecting a subsequent predetermined limited horizontal movement along the horizontal lienar path of one of the blade holder and grinder to sharpen the blade cutting edge by grinding a predetermined amount of material from the blade by said limited horizontal movement as the other of said blade holder and grinder is reciprocated along its horizontal linear path causing momentary linear crossing contact between the grinding wheel and the blade cutting edge.   
     
     
       28. The sharpening device defined in claim 27 in which the blade holder housing is pivotally mounted on a platform; and in which the platform is mounted on slide rails located on the base to provide movement of the blade holder along its horizontal linear path. 
     
     
       29. The sharpening device defined in claim 27 in which the electric motor is reversible.